From the Guidelines
Voriconazole does not have reliable activity against Mucorales fungi. Voriconazole is an antifungal medication that works well against many fungi including Aspergillus species, Candida species, and certain molds, but it specifically lacks effectiveness against the Mucorales order (formerly called Zygomycetes), which cause mucormycosis.
Key Points
- For mucormycosis infections, first-line therapy is typically amphotericin B (particularly liposomal formulations at doses of 5-10 mg/kg/day), often followed by posaconazole or isavuconazole for step-down therapy.
- The lack of activity against Mucorales is due to voriconazole's mechanism of action, which involves inhibiting the fungal cytochrome P450-dependent enzyme lanosterol 14-α-demethylase.
- Mucorales fungi have natural resistance to voriconazole through altered target binding or efflux mechanisms, as noted in studies such as 1.
- In fact, there have been reports of breakthrough mucormycosis in patients receiving voriconazole prophylaxis, suggesting that voriconazole use might even be associated with increased risk of mucormycosis in certain immunocompromised populations.
Treatment Options
- Amphotericin B and posaconazole are the most active drugs in vitro against Mucorales, as shown in studies such as 1.
- The comparative activities of amphotericin B and posaconazole may vary depending on the genus and species of the infecting strain.
- Species-specific differences in azole and terbinafine susceptibilities are noted particularly for Rhizopus and Mucor, highlighting the importance of species identification in guiding treatment decisions 1.
From the Research
Voriconazole Activity Against Mucorales
- There is limited information available on the effectiveness of voriconazole against Mucorales 2, 3.
- According to a study published in 2016, voriconazole is not typically used as a first-line treatment for mucormycosis, but it may be considered in certain cases, such as when the patient is intolerant to other antifungal agents or when the infection is caused by a fungus that is resistant to other treatments 3.
- Another study published in 2007 notes that voriconazole has broad-spectrum activity against various fungi, including Aspergillus spp, Fusarium spp, and Scedosporium apiospermum, but it does not specifically mention Mucorales 4.
- A 2006 review of voriconazole's efficacy against various fungal infections also does not mention Mucorales specifically, but it does note that the drug has broad-spectrum activity against many types of fungi 5.
- A 2015 review of voriconazole's use and efficacy notes that it is effective against many types of fungi, including Aspergillus spp and other hyaline molds, but it does not specifically mention Mucorales 6.
Summary of Findings
- The available evidence suggests that voriconazole is not typically used as a first-line treatment for mucormycosis, and its effectiveness against Mucorales is not well established 2, 3.
- Further research is needed to determine the efficacy of voriconazole against Mucorales and to establish its potential role in the treatment of mucormycosis 3.